The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, there is shown in the drawings an embodiment that is presently preferred, in which like numerals represent similar parts throughout the several views of the drawings, it being understood, however, that the invention is not limited to the specific methods and instrumentalities disclosed.
Each of the fluorescent lamps 102 is coupled to one of the digital electronic dimming ballasts 110 for control of the intensities of the lamps. The ballasts 110 are operable to communicate with each other via digital ballast communication links 112. A common communication protocol used for digital ballast communication links is the digital addressable lighting interface (DALI) protocol. However, the present invention is not limited to ballasts 110 and digital ballast communication links 112 using the DALI protocol.
The digital ballast communication links 112 are also coupled to digital ballast controllers (DBCs) 114, which provide the necessary direct-current (DC) voltage to power the communication links 112, as well as assisting in the programming of the lighting control system 100. Each of the ballasts 110 is operable to receive inputs from a plurality of sources, for example, an occupancy sensor (not shown), a daylight sensor (not shown), an infrared (IR) receiver 116, or a wallstation 118. The ballasts 110 are operable to transmit digital messages to the other ballasts 110 in response to the inputs received from the various sources. Preferably, up to 64 ballasts 110 are operable to be coupled to a single digital ballast communication link 112.
The ballasts 110 may receive IR signals 120 from a handheld remote control 122, e.g., a personal digital assistant (PDA), via the IR receiver 116. The remote control 122 is operable to configure the ballast 110 by transmitting configuration information to the ballasts via the IR signals 120. Accordingly, a user of the remote control 122 is operable to configure the operation of the ballasts 110. For example, the user may group a plurality of ballasts into a single group, which may be responsive to a command from the occupancy sensor. Preferably, a portion of the programming information (i.e., a portion of a programming database) is stored in memory of each of the ballasts 110. An example of the method of using a handheld remote control to configure the ballasts 110 is described in greater detail in co-pending commonly-assigned U.S. patent application Ser. No. 11/375,462, filed Mar. 13, 2006, entitled HANDHELD PROGRAMMER FOR LIGHTING CONTROL SYSTEM, the entire disclosure of which is hereby incorporated by reference.
Referring back to
A plurality of processors 140 allow for communication between a personal computer (PC) 150 and the load control devices, i.e., the ballasts 110 and the electronic drive units 130. Each processor 140 is operable to be coupled to one of the digital ballast controllers 114, which is coupled to the ballasts 110 on one of the digital ballast communication links 112. Each processor 140 is further operable to be coupled to the shade controller 136, which is coupled to the motorized roller shades 114 on one of the shade communication links 114. The processors 140 and the PC 150 are coupled to an inter-processor link 152, e.g., an Ethernet link, such that the PC 150 is operable to transmit digital messages to the processors 140 via a standard Ethernet switch 154.
The PC 150 operates as a central controller for the lighting control system 100 and executes a graphical user interface (GUI) software, which is displayed on a display screen 156 of the PC. The GUI allows the user to configure and monitor the operation of the lighting control system 100. During configuration of the lighting control system 100, the user is operable to determine how many ballasts 110, digital ballast controllers 114, electronic drive units 130, shade controllers 136, and processors 140 that are connected and active using the GUI software. Further, the user may also assign one or more of the ballasts 110 to a zone or a group, such that the ballasts 110 in the group respond together to, for example, an actuation of the wallstation 118. The PC 150 includes a memory for storing the programming data of the lighting control system 100. The PC 150 is operable to transmit an alert to the user in response to a fault condition, such a fluorescent lamp that is burnt out. Specifically, the PC 150 sends an email, prints an alert page on a printer, or displays an alert screen on the screen 156.
The back end 220 includes an inverter 250 for converting the DC bus voltage to a high-frequency AC voltage and an output circuit 260 comprising a resonant tank circuit for coupling the high-frequency AC voltage to the lamp electrodes. A balancing circuit 270 is provided in series with the three lamps L1, L2, L3 to balance the currents through the lamps and to prevent any lamp from shining brighter or dimmer than the other lamps. The front end 210 and back end 220 of the ballast 110 are described in greater detail in commonly-assigned U.S. Pat. No. 6,674,248, issued Jan. 6, 2004, entitled ELECTRONIC BALLAST, the entire disclosure of which is hereby incorporated by reference.
A control circuit 280 generates drive signals to control the operation of the inverter 250 so as to provide a desired load current to the lamps L1, L2, L3. The control circuit 280 is operable to control the intensity of the lamps L1, L2, L3 from a low-end trim (i.e., a minimum intensity) to a high-end trim (i.e., a maximum intensity). A power supply 282 is connected across the outputs of the rectifier 230 to provide a DC supply voltage, VCC, which is used to power the control circuit 280. A communication circuit 284 is coupled to the control circuit 280 and allows the control circuit 280 to communicate with the other ballast 110 on the digital ballast communication link 112. The ballast 110 further comprises a plurality of inputs 290 having an occupancy sensor input 292, a daylight sensor 294, an IR input 296, and a wallstation 298 input. The control circuit 280 is coupled to the plurality of inputs 290 such that the control circuit 280 is responsive to the occupancy sensor, the daylight sensor, the IR receiver 116, and the wallstation 118 of the lighting control system 100. The control circuit 280 is operable to determine a setpoint, i.e., the desired intensity of the connected lamp 102, in response to the communication circuit 284 and the plurality of inputs 290. The control circuit 280 is also coupled to a memory 286 for storage of the operational information of the ballast 110, e.g., the setpoint, the high-end trim, the low-end trim, a serial number, etc.
An example of a digital electronic dimming ballast operable to be coupled to a communication link and a plurality of other input sources is described in greater detail in co-pending commonly-assigned U.S. patent application Ser. No. 10/824,248, filed Apr. 14, 2004, entitled MULTIPLE-INPUT ELECTRONIC BALLAST WITH PROCESSOR, and U.S. patent application Ser. No. 11/011,933, filed Dec. 14, 2004, entitled DISTRIBUTED INTELLIGENCE BALLAST SYSTEM AND EXTENDED LIGHTING CONTROL PROTOCOL. The entire disclosures of both applications are hereby incorporated by reference.
During normal operation of the lighting control system 100, the PC 150 communicates with the ballasts 110 and the electronic drive units 130 using a polling technique. The PC 150 polls the load control devices by transmitting a polling message to each of the ballasts 110 and electronic drive units 130 in turn. To send a polling message to a specific ballast 110, the PC 150 transmits the polling message to the processors 140. If a processor 140 that receives the polling message is coupled to the digital ballast controller 114 that is connected to the specific ballast 110, the processor 140 re-transmits the polling message to the digital ballast controller 114. Upon receipt of the polling message, the digital ballast controller 114 simply re-transmits the polling message to the specific ballast 110.
In response to receiving the polling message, the specific ballast 110 transmits a status message to the PC 150. The status message is transmitted in a relaying fashion back to the PC 150, i.e., in a reverse order than how the polling message is transmitted from the PC 150 to the ballast 110. Preferably, the status message includes the present intensity of the fluorescent lamp. For example, the ballast 110 may transmit the present intensity as a number between 0 and 127 corresponding to the percentage between off (i.e., a number of 0) and the high-end value (i.e., a number of 127).
According to the present invention, the PC 150 estimates a total power consumption of the lighting control system 100 (i.e., a power usage value) using one or more operational characteristics of the ballasts 110 rather than using power meters or current transformers to measure the actual input current of the ballasts. Preferably, the PC 150 simply determines the total amount of power presently being consumed by the lighting control system 100 in response to the number, wattage, and type of lamps 102 connected to the ballasts 110 and the present intensities of the ballasts. Alternatively, a single ballast 110 could be operable to estimate the power consumption of the ballast rather than the PC 150 performing the computation.
The PC 150 is operable to determine the power presently being consumed by each of the ballasts 110 by using the present intensity of each ballast and one of a plurality of ballast power consumption tables 300. A unique ballast power consumption table 300 (i.e., a look-up table) for each type of ballast is stored in the memory of the PC 150. An example of the format of the ballast power consumption tables 300 is shown in
The PC 150 determines the power consumption of each ballast by locating the power consumption amount in the second column 320 of the table 300 adjacent the intensity value (that was received from the ballast 110) in the first column 310. For example, if the PC 150 receives an intensity level of three (3) from the ballast 110, the PC 150 assumes that the ballast is presently consuming an amount of power of P3. Once the PC 150 has determined the power consumption of each of the ballast 110 in the lighting control system 100, the PC can sum the power consumption values to determine the total power consumption of the lighting control system 100. Preferably, the PC 150 is operable to display (i.e., graphically represent) the total estimated power consumption of the lighting control system 100 on the screen 156 of the PC. Alternatively, each ballast 110 could store the appropriate power consumption table 300 in the memory 286. Each ballast 110 could then determine the power consumption using the present intensity, and simply transmit the present power consumption to the PC 150.
The PC 150 is operable to use the estimated total power consumption as part of a load shedding procedure 400 (shown in
The automatic load shedding mode provides for automatic control of the lamps 102 in response to the power consumption exceeding the load shedding power threshold, rather than requiring a building manager to intervene. During the automatic load shedding mode, the PC 150 dims the lamps in response to the load shedding condition using load shedding “tiers”. A tier is defined as a combination of predetermined load shed parameters (i.e., load shedding amounts) for each of the individual electrical loads or groups of electrical loads. For example, “Tier 1” may comprise shedding loads in an office space by 20%, in a hallway space by 40%, and in a lobby by 10%, while “Tier 2” may comprise shedding loads in the office space by 30%, in the hallway space by 50%, and in the lobby by 30%. Preferably, each successive tier reduces the amount of power being delivered to the electrical loads. Accordingly, the PC 150 is operable to consecutively step through each of the tiers to continue decreasing the total power consumption of the lighting control system 100 if the total power consumption repeatedly exceeds the load shedding threshold.
Preferably, the PC 150 controls each of the ballasts 110 to consume less power by transmitting the load shed parameter (which is chosen according to the next load shedding tier) to each of the ballasts. The load shed parameter represents a level of desired load shedding to be applied to the setpoint determined by the control circuit 280 of each of the ballasts 110 (i.e., the load shed parameter represents a percentage of the present setpoint). After determining the setpoint in response to the communication circuit 284 and the plurality of inputs 290, the control circuit 280 of each ballast 110 preferably multiples the setpoint by a factor that is dependent upon the load shed parameter, as will be described in greater detail below. Since the load control system 100 does not simply reduce the high-end trim of the ballasts 110 in response to the total power consumption exceeding the load shedding power threshold (as in some prior art load control systems), the load control system always controls the lamps 102 to a lower intensity during the load shedding procedure 400 of the present invention, even if the ballasts 110 are receiving inputs from occupancy sensors and daylight sensors.
If the PC 150 receives a status message back from the polled ballast 110 at step 412, the PC determines the present power consumption of the polled ballast 110 using the intensity level from the status message and the appropriate ballast power consumption table 300 at step 416. To determine which of the plurality of ballast power consumption tables 300 that are stored in memory to use, the PC 150 uses the information about the ballast 110 (i.e., the type of the ballast, the wattage, number of lamps, etc.), which is part of the database stored in memory. At step 418, the PC 150 determines the total power consumption by summing the present power consumption of the each of the individual ballasts 110. At step 420, the PC 150 displays the total power consumption from step 418 on the screen 156.
If the load shedding threshold is exceeded at step 422, a determination is made at step 424 if the automatic load shedding mode is enabled. If so, the PC 150 determines if there are more load shedding tiers to implement at step 426. If there are more load shedding tiers to implement at step 426, the PC controls the ballasts 110 to the intensity levels set by the next tier at step 428. As previously mentioned, the PC 150 updates a load shed parameter of each of the ballasts according to the next tier. Preferably, the load shed parameter has a value that ranges between zero (0) and 100, such that a load shed parameter of zero corresponds to no load shedding, while a load shed parameter of 100 causes the lamp 102 to be turned off. For example, the PC 150 may transmit a load shed parameter of 20 to a first ballast and a load shed parameter of 40 to a second ballast. Accordingly, the first ballast will store the value 20 as its load shed parameter and the second ballast will store the value 40 as its load shed parameter using a load shed parameter update procedure 500.
Once the ballast 110 has stored the load shed parameter in memory, the ballast uses a setpoint procedure 600 to determine a lighting setpoint (which controls the intensity of the lamp 102) from the load shed parameter.
Further, the control circuit 280 uses a daylighting high-end trim (DAY_HET), which represents the high-end trim of the ballast 110 determined from a daylight reading of a connected daylight sensor using a daylighting algorithm. Preferably, the daylighting algorithm attempts to maintain the total illumination (from both daylight and artificial light, i.e., from the lamps 102) in the space in which the ballasts 110 and the daylight sensor are located substantially constant. The daylighting algorithm accomplishes this goal by decreasing the value of the daylighting high-end trim if the total illumination in the space increases, and increasing the value of the daylighting high-end trim if the total illumination decreases. Examples of daylighting algorithms are described in greater detail in commonly-assigned U.S. Pat. No. 4,236,101, issued Nov. 25, 1980, entitled LIGHT CONTROL SYSTEM, and U.S. Pat. No. 7,111,952, issued Sep. 26, 2006, entitled SYSTEM TO CONTROL DAYLIGHT AND ARTIFICIAL ILLUMINATION AND SUN GLARE IN A SPACE. The entire disclosures of both applications are hereby incorporated by reference.
Referring to
If an occupancy sensor that is connected to the ballast 110 is signaling that the space is occupied at step 612, a determination is made at step 614 as to whether the occupancy high-end trim OCC_HET is less than the present setpoint. If so, the setpoint is set to the occupancy high-end trim OCC_HET at step 616 and the procedure 600 continues on to step 618. If the space is not occupied at step 612 or the occupancy high-end trim OCC_HET is not less than the present setpoint at step 614, the procedure 600 continues on to step 618, where a determination is made as to whether a daylighting algorithm is enabled. If the daylighting algorithm is enabled at step 618 and the daylighting high-end trim DAY_HET is less than the present setpoint at step 620, the setpoint is set to the daylighting high-end trim DAY_HET at step 622 and the setpoint is stored in memory at step 624. If the daylighting algorithm is not enabled at step 618 or if the daylighting high-end trim DAY_HET is not less than the present setpoint at step 620, the present setpoint is simply stored in memory at step 624.
At step 626, the setpoint is updated based on the load shed parameter that was received during the load shed parameter update procedure 800 of
Setpoint=Setpoint·(100−Load Shed Parameter)/100. (Equation #1)
For example, if no load shedding is desired, the load shed parameter is zero and the setpoint is not changed according to Equation #1. Further, if the load shed parameter is 100, the setpoint is equal to zero, and thus, the ballast 110 turns the lamp 102 off. A load shed parameter between zero and 100 causes the setpoint to be scaled accordingly. The setpoint procedure 600 exits at step 628.
Therefore, the PC 150 is operable to cause a ballast 110 to begin load shedding by transmitting a load shed parameter having a value greater than zero to the ballast 110. The control and logic in regards to determining the values of the load shed parameters and determining when to automatically shed loads (i.e., if automatic load shedding mode is enabled) is executed by the PC 150.
Referring back to
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.
This application claims priority from commonly-assigned U.S. Provisional Application Ser. No. 60/851,383, filed Oct. 13, 2006, and U.S. Provisional Application Ser. No. 60/858,844, filed Nov. 14, 2006, both entitled LIGHTING CONTROL SYSTEM. The entire disclosures of both applications are hereby incorporated by reference.
Number | Date | Country | |
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60851383 | Oct 2006 | US | |
60858844 | Nov 2006 | US |